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ATLANTA (CNN) -- Ever since our ancestors first started making tools, humanity has been trying to go beyond its limitations to improve on the way our bodies interact with nature.

Over thousands of years we have been able to develop the way we work with, and adapt to, our environment by using an increasingly sophisticated array of tools. Now high-tech tools, implanted or attached to the human body, are bringing biology and technology together to repair, replace and augment human ability.

"We are the species that goes beyond our limitations," says futurist Ray Kurzweil.

"The science of control and communications in the animal and machine," is how American mathematician Norbert Wiener defined cybernetics. The fields of neuroscience, biomechanics, robotics, mathematics, computer science, materials science and tissue engineering all play a role in the effort to use machines to help patients who have lost some control over their bodies, whether through accident or disease.

"By merging human and machine, by creating that intimacy," says Hugh Herr of the MIT Biomechatronics Group, "we will truly be able to rehabilitate people."

Using our ingenuity to replace lost functionality isn't new. A simple stick, used to help someone walk, might be one of the first examples. In the 16th century, French physician Ambrose Pare began implanting artificial teeth, eyes and limbs made of silver and gold. Prosthetics greatly improved in both form and function during the last century.

But new technologies and our growing understanding of the brain and nervous system means that simply replacing lost form isn't enough anymore. Scientists are moving, in a variety of ways, to restoring and lost and augmenting normal function as well. "The field is marching towards a future," says Herr, "where there's a blurring of the boundaries between the synthetic aspects of the prosthesis and the person's body; blurring the boundaries between synthetics and cells and tissues."

Signals from the brain

The key issue: Understanding the human brain and how it interacts with the body and the world around it.

"Even the most advanced neuroscientist would admit that the brain is unbelievably complicated," says Brown University neuroscientist and CNN Future Summit Committee Member John Donoghue, "and we're still scratching the surface of really understanding what's going on inside the brain."

For decades, neuroscientists have been unlocking the mysteries of the human brain, from identifying the locations where key functions take place to the nature of the electrical impulses between neurons that carry information, "kind of like a Morse code," says Donoghue.

One of the big breakthroughs according to Donoghue has been the ability to intercept that code. "We can read out those signals, and by some not-to-complex mathematical techniques, we can put them back together in a way that we can interpret what the brain is trying to do."

Putting the technology to work

Restoring the connection between the brain and body through technology has many applications.

One of the most well known is Cochlear implants. These devices, implanted in the ear, turn sound into electrical impulses. Transmitted to the brain, these signals allow the deaf to hear. While the technology currently doesn't restore what might be considered normal hearing, patients with the implants can understand well enough to carry on a conversation.

Artificial limbs are also becoming much more sophisticated. "Right now artificial limbs are really separate from the human body," says Herr. "I'm an amputee and when I go to bed at night, I actually take off my legs. So they're like these fancy shoes, and I really don't have a relationship with them. That is to say, every five years when I get new prosthesis, I don't cry or anything. But there will be a day when amputees are wired up electrically, they're wired up mechanically, and it's really a part of their body, although aspects of the prosthesis may still be synthetic."

Robotics, tissue engineering and materials science all have a role in creating the future of prosthetic limbs.

"The prosthesis forty or fifty years out," says Herr, "would have synthetic components that may be better or stronger than bones or ligaments, and perhaps other components that are tissues, that are still superior to synthetic constructs." The result, Herr believes, is that "amputees will not only be able to walk across a sandy beach, but will be able to feel the sand against their synthetic foot."

Another profound application is restoring the ability of the brain to communicate with and manipulate other parts of the body. Patients who have suffered from spinal injury or disorders that affect the nervous system will benefit.

The chip helps restore movement to paralyzed patients.

One example is BrainGate, a tiny chip that Donoghue helped to develop. Once implanted, BrainGate, helps restore movement to paralyzed patients. (Full story)

In Atlanta, Phillip Kennedy is developing a system that will allow patients who have lost the ability to communicate to speak again. His solution involves transmitting neural signals in the speech center of the brain to a computer, which is learning to speak for the disabled patient.

Recreating the connections between the brain and the body may sound like science fiction, but its just the beginning. "We are working on recreating an artificial nervous system," says Donoghue. "We are working on ways that will transform the electrical impulses of the brain into light, and that that light will then be used as an artificial nervous system using fiber optics to transmit that information to the muscles. Then converted back into electrical stimulation where it can stimulate the arm and we'll re-animate the limb."

Beyond human ability

"We're now building leg exoskeletons which are robotic structures that run in parallel to the human limb," says Hugh Herr from the MIT Biomechanics Lab. "Our goal is to make legged movements very easy. So imagine a future where instead of a bicycle rack, you go to a leg rack, and strap on these fancy pants and you'll be able to run anywhere your legs can take you, but without breathing hard. So imagine running through the wilderness, day after day, sixty miles a day, jumping over logs, over rocks."

"We will be putting more and more robotic technology inside us," says MIT Robotics Lab Director and CNN Future Summit Nominating Committee Member Rodney Brooks. "Robotic joints, replacement limbs, a lot of people now, over a 100,000, have cochlear implants, with direct neural implants into their cochlear, so they can hear. As us baby boomers get older and older, we're going to be looking for all sorts of replacement parts. We're going to become partially robotic. What's a robot, what's us, is starting to get a bit messy."

We already augment our intelligence by using computers: A quick Internet search helps us find information faster than ever before. Perhaps in the not so distant future, we'll be augmenting our intelligent directly, through implants or other direct connections between your brain and machines, something envisioned for decades in science fiction, from William Gibson's seminal cyberpunk novel "Neuromancer" to the film "The Matrix."

Ray Kurzweil envisions a future where there are no sharp distinctions between human and machine. "You're not going to be able to walk into a room in 2035 and say humans on the left side of the room, machines on the right. You'll have a hard time finding a human who doesn't have extensive amounts of technology inside them in the form of nanobots and other systems that are keeping them healthy and also extending their range of experiences and their intelligence."